On Wednesday, the department announced regulations that would require airlines to refund baggage fees if the bag is lost and standardize those fees for code-share partners. It also would increase compensations for bumped passengers and require foreign airlines to limit tarmac waits to four hours. (Waits on domestic airlines are already limited to three hours.)

"Overall it’s a giant improvement for consumers," Charlie Leocha, director of the Consumer Travel Alliance, a Washington, D.C. advocacy group, said of the new rules. "It’s the biggest change since deregulation."

The 1978 Airline Deregulation Act, among other changes, removed governmental control from airline pricing. Consumers benefited by the competition among airlines in terms of lower fares.

Leocha rated the latest regulations, which will go into effect later this year, a "10" on a 10-point scale. "Everything is moving forward in favor of the passengers," he said. "DOT deserves enormous kudos for doing this."

But the rules do not go as far as Leocha and some others would like in demanding transparency in airfare pricing.

In its ruling, the department said airlines must show so-called ancillary fees, such as those charged for baggage, clearly on their websites. Many of them do that already, Leocha noted. He said he hoped the fees would be incorporated into the pricing structure in a way that allows for direct price comparisons.

This ruling means that such information is available but that passengers using a third-party website, such as Travelocity or Orbitz, must switch back and forth between the booking site and the airline site, Leocha said.

The press for pricing transparency isn’t over, he noted because the department may issue yet another set of rules.

Meanwhile, congressional action may mandate that transparency. The Senate version of a bill to reauthorize the Federal Aviation Administration would require airlines to make those fees crystal clear. The House version of that bill does not contain that language. A conference committee on the matter is to begin work next month.